Team MightyBoy

Hi all.
just in case the repair of my current f8b manual gearbox does not go well i am wondering if there is any other 5 speed gearbox that will bolt directly into the engine and into the MightyBoy's chassis without or minimal modification?

Import F6A/F5A gearbox is the easiest fit, but most difficult to find. Anything else (Swift, Matiz, etc) will require a lot of fabrication and flywheel work.